Electrical plan symbols, the complete chart (IEC and US)
Every symbol on an electrical floor plan in the IEC 60617 and the US convention, from the socket to the board, with a drawn room to read them on and a chart of all 71 devices you can search.
Electrical plan symbols are the small standard marks on an electrical floor plan that stand for the sockets, switches, lights, detectors and the board of an installation. Two families are in use: the IEC 60617 symbols drawn in Europe and most of the world, and the US symbols descended from the ANSI and NECA standards. The devices are the same. The marks and the names differ, and this page shows both.
The symbols on a room
Start with one room. The light in the middle of the ceiling, the switch that controls it beside the door, three double sockets on the walls, and the board in the hall outside. The blue line is the lighting circuit, the red one the socket circuit. Switch the drawing between the two conventions and watch the marks change while the room stays the same.
Three things to notice. The socket's open semicircle becomes a circle with two short lines, the switch's circle with a stroke becomes a letter S, and the lamp is the same crossed circle in both. The words move more than the marks: socket and receptacle, distribution board and panel.
The twelve you will meet on every plan
| Device | IEC | US | What it means on the plan |
|---|---|---|---|
| Single socket | One outlet in the wall. US: single receptacle. | ||
| Double socket | Two outlets in one box. US: duplex receptacle. | ||
| RCD socket | A socket that trips when current leaks to earth. US: GFCI receptacle. | ||
| Cooker control | The switched feed for the cooker. US: range outlet. | ||
| One-way switch | A light switched from one place. US: single-pole, S. | ||
| Two-way switch | One of a pair switching a light from two places. US: three-way, S3. | ||
| Intermediate switch | The switch in the middle when three places control one light. US: four-way, S4. | ||
| Dimmer | A switch that also sets the brightness. | ||
| Ceiling light | A luminaire on the ceiling. | ||
| Wall light | A luminaire on the wall, drawn against the wall line. | ||
| Smoke detector | A smoke alarm, usually on the ceiling of a hall or landing. | ||
| Distribution board | Where every circuit starts. US: panel. |
Sockets and power
The IEC single socket is an open semicircle on a short stem, the stem crossing the wall line. A double socket carries a small 2. The US drawing is a circle with two lines through it, the duplex receptacle, and a single receptacle has one line.
Special sockets add a letter or two: RCD in Europe, GFCI in America, for the socket protected against current leaking to earth. An outdoor socket, a floor socket and a shaver socket each have a mark of their own. The larger loads get their own symbols too: the cooker control, the fused spur that feeds a fixed appliance through its own fuse, the three-phase socket in a workshop.
Switches
An IEC switch is a small circle with a stroke leaving it at an angle, the stroke standing for the lever. A two-way switch has two strokes, an intermediate switch a crossbar. The US drawing uses letters instead: S for a single-pole switch, S3 for a three-way switch, S4 for a four-way. A three-way switch is the same device Europe calls two-way. One side counts terminals, the other counts positions, and nothing about the wiring differs. The two-way switching article lets you flick a pair and see why.
Dimmers, pull cords, double-pole switches, push buttons, time switches and motion-sensing switches each have a mark, usually the switch mark with a letter or a small symbol beside it.
Lighting
A ceiling light is a circle with a cross through it in both conventions. A wall light sits against the wall line. A recessed light is a smaller mark, a fluorescent fitting a long bar, an emergency light carries its own mark so it is never confused with the rest. Outdoor lights, floodlights, LED strips, track lights, pendants and exit signs all have symbols, which matters on a plan where the fitting type decides the circuit.
The board and the rest
The distribution board, the consumer unit in a house, is a rectangle with a hatch across it; in American drawings it is the panel. Every circuit on the plan starts there, which is why every check of a plan starts there too.
Beyond power and light, a plan carries the safety and comfort devices: smoke, heat and carbon monoxide detectors, the call point and the sounder of a fire alarm, the thermostat, the extractor fan, the data outlet and the TV outlet, the doorbell, the camera, the EV charger. Each is a small mark that says what is there without a word.
Labels and circuits
A symbol usually carries a short label: S1, S2 for the switches, L1 for a light, SO3 for a socket. The labels tie the plan to the schedule, the list of what is on each circuit, and tie each switch to its light. On a coloured plan every symbol on one circuit shares a colour with its wires, so the lighting circuit and the kitchen sockets can be told apart at a glance.
Every device, in both conventions
All 71 devices the app draws, in the nine groups of its palette. Switch the chart between conventions and search by either name. Print this page for the chart on paper.
Common mistakes with symbols on a plan
- A sketch instead of a symbol. A little drawing of a socket is clear to the person who drew it and to nobody else. Use the mark.
- A wall device floating in the room. A socket or a switch sits on the wall line, its open side into the room. Away from the wall it reads as a floor socket.
- A switch with no light. Every switch mark should be drawn to the light it controls, and a two-way pair to each other as well.
- Mixed conventions on one sheet. An S beside a semicircle socket makes the reader guess which family the rest follows. Pick one for the sheet, or show the convention in the legend.
- No legend. The symbols mean what the legend says. A sheet without one is read by assumption.
Questions
What does S3 mean on an electrical plan?
In the US convention S3 is a three-way switch, one of a pair that controls a light from two places. In the IEC convention the same device is a two-way switch, drawn as a circle with two strokes, and S3 would just be the label of the third switch on the plan.
What is the symbol for a GFCI outlet?
In US drawings a duplex receptacle with the letters GFCI (or GFI, or WP for a weatherproof one) beside it. In IEC drawings the same device is the RCD socket, the socket mark with RCD beside it.
Is there a PDF of these symbols?
Print this page: the chart above prints with the symbols in whichever convention is showing. The app draws the same symbols on the plan and lists the ones used in the legend of every export.
Why do the IEC and US symbols differ at all?
They grew from different standards bodies, IEC 60617 on one side and ANSI Y32 and later NECA 100 on the other, and each was in use long before the other was common. Both describe the same devices, which is why a plan can be shown in either. The IEC vs US article goes through the differences word by word.